Risk factors for intraamniotic infection: a prospective epidemiologic study.

To determine the cumulative incidence of intraamniotic infection in our hospital and to identify potential risk factors for infection, 408 consecutive patients were followed up prospectively to determine development of intraamniotic infection. The clinical diagnosis of intraamniotic infection was made in 43 (10.5%) patients. Patients with intraamniotic infection were younger, of lower gravidity and parity, more likely to require oxytocin augmentation, and more likely to be monitored internally than were patients who were not infected. They also had longer durations of labor, ruptured membranes, and hospitalization before delivery, had significantly more vaginal examinations, and were more likely to be delivered of infants by cesarean section, as compared with patients without infection. Logistic regression analysis identified four variables independently associated with intraamniotic infection: the number of vaginal examinations, duration of ruptured membranes, use of internal monitors, and duration of total labor. Further study is necessary to clarify the role of these risk factors in the pathogenesis of intraamniotic infection so that infection control strategies can be developed.